Traumatic brain injury (TBI) is a signature condition of combat among returnees from Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF). VA's goals regarding TBI are to (1) screen every OEF/OIF Veteran for the possibility of TBI; (2) evaluate each Veteran who screens positive, using the 22-item Neurobehavioral Symptom Inventory (NSI-22) in combination with a comprehensive history and physical examination; and then (3) develop a treatment plan including recommended referrals to appropriate services based on the assessment. The latter two elements constitute the comprehensive TBI evaluation (CTE). This proposal builds on a recently-completed study (SDR 08-405) in which the present researchers were funded to examine the impact of patient and medical facility factors affecting differential rates of progression to the CTE among Veterans with a positive initial screening for TBI, and assess differential rates of TBI diagnosis and participation in post-CTE follow-up care. We also examined the structure of persistent post-concussive symptoms by assessing the dimensionality and psychometric properties of the NSI-22. The present proposal's overall aim is to move beyond screening and evaluation to examine the course of persistent PCS and impacts on Veterans' functioning at personal, family and broader community levels. Within this overarching aim, we propose three research objectives: Objective 1: Identify clusters of persistent post-concussive symptoms (syndromes) and their associated demographic, co-morbidity and etiological factors among Veterans with a CTE. Objective 2: Identify VA utilization and costs related to each syndrome. Objective 3: Assess the course of symptom severity within syndromes over time and relationships to short- and long-term reintegration in multiple domains, controlling for utilization. Objective 1 uses analysis of national CTE data combined with data from other VA files. It builds on our extensive prior use of the files to identify the dimensional structure of persistent PCS assessed by the NSI-22. Based on prior work, we expect to identify distinct patterns of symptom severity (syndromes) across the four dimensions of the NSI-22: somato-sensory, vestibular, affective and cognitive. We expect to use these syndromes for analyses of recovery and reintegration over time, but if there are no distinct syndromes, we will track symptom severity on the four NSI-22 dimensions independently for Objectives 2 and 3. For Objective 1 we will also examine the relationship between Veteran characteristics in three domains - demographics, injury etiology, and mental health co-morbidities - and their neurobehavioral symptoms. A key point is that we can study the relationships using the four NSI-22 dimensions separately or as symptom clusters (syndromes). Hereafter we refer to syndromes as convenient short-hand for either clusters of symptoms (if discovered) or alternatively the individual NSI-22 symptom dimensions. Our ultimate interest in the identification of syndromes under Objective 1 is to understand their relationship to meaningful clinical, personal and social outcomes in both the short and long term. To adequately pursue this objective will require the collection of new data. We therefore propose to administer a comprehensive measure of community reintegration along with the NSI-22 to a cohort of OEF/OIF Veterans at 6 and 18 months following their CTE. The reintegration measure developed by Sayer and colleagues was specifically designed for the Veteran population and assesses reintegration problems in 24 specific areas within the broader domains of self-care, interpersonal relations with family, friends and others, work, and participation in civil society more generally.